Free radical-mediated aryl amination and its use in a convergent [3 + 2] strategy for enantioselective indoline α-amino acid synthesis

Journal of the American Chemical Society

Volumn 125, Issue 1, 2003, Pages 163-168

  Viswanathan, Rajesh ^a   Prabhakaran, Erode N ^a   Plotkin, Michael A ^a   Johnston, Jeffrey N ^a  

^a INDIANA UNIVERSITY   (United States)

Author keywords

[No Author keywords available]

Indexed keywords

ENANTIOMERS;

ADDITION REACTIONS; AMINO ACIDS; CHEMICAL BONDS; FREE RADICAL REACTIONS; PH; PHASE TRANSITIONS; REDUCTION; SYNTHESIS (CHEMICAL);

AMINATION;

ALKANE; AMINO ACID DERIVATIVE; AZIDE; AZO COMPOUND; CARBON; FREE RADICAL; FUNCTIONAL GROUP; GLYCYLIMINE; IMINE; INDOLE DERIVATIVE; NITROGEN; PHENYLALANINE DERIVATIVE; STANNANE; UNCLASSIFIED DRUG;

ALKYLATION; AMINATION; AMINO ACID SYNTHESIS; ARTICLE; CHEMICAL BINDING; CHEMICAL BOND; CYCLIZATION; ENANTIOMER; ENANTIOSELECTIVITY; PH; REDUCTION;

AMINATION; AMINO ACIDS; ELECTROSTATICS; FREE RADICALS; INDOLES; PHENYLALANINE; STEREOISOMERISM;

EID: 0037425527     PISSN: 00027863     EISSN: None     Source Type: Journal    
DOI: 10.1021/ja0284308     Document Type: Article

References (77)

1. (a) Fallis, A. G.; Brinza, I. M. Tetrahedron 1997, 53, 17543.
2. (b) Friestad, G. K. Tetrahedron 2001, 57, 5461.
3. (c) Ollivier, C.; Renaud, P. In Radicals in Organic Synthesis; Renaud, P., Sibi, M., Eds.; Wiley-VCH: Weinheim, 2001; Vol. 2, pp 93-112.
4. (a) Corey, E. J.; Pyne, S. G. Tetrahedron Lett. 1983, 24, 2821.
5. (b) Hart, D. J.; Seely, F. L. J. Am. Chem. Soc. 1988, 110, 1631.
6. (c) Bartlett, P. A.; McLaren, K. L.; Ting, P. C. J. Am. Chem. Soc. 1988, 110, 1633.
7. For leading references, see: Hart, D. J. In Radicals in Organic Synthesis; Renaud, P. Sibi, M., Eds.; Wiley-VCH: Weinheim, 2001; Vol. 2, pp 279-302.
8. There are also reports of nonradical carbon additions to heteroatoms: azomethine nitrogen: Lin, J.-M.; Koch, K.; Fowler, F. W. J. Org. Chem. 1986, 51, 167; carbonyl oxygen: Chi. S.; Heathcock, C. H. Org. Lett. 2000, 2, 1.
9. There are also reports of nonradical carbon additions to heteroatoms: azomethine nitrogen: Lin, J.-M.; Koch, K.; Fowler, F. W. J. Org. Chem. 1986, 51, 167; carbonyl oxygen: Chi. S.; Heathcock, C. H. Org. Lett. 2000, 2, 1.
10. Acyl radical addition to carbonyl: Rust. F. F.; Seubold, F. H.; Vaughan, W. E. J. Am. Chem. Soc. 1948, 70, 3258. (a) Kaplan, L. J. Am. Chem. Soc. 1966, 88, 1833. (b) Urry, W. H.; Nishihara, A.; Niu, J. H. Y. J. Org. Chem. 1967, 32, 347. (c) Harrison, D. A.; Schwartz, R. N.; Kagan, J. J. Am. Chem. Soc. 1970, 92, 5793. (d) Mendenhall, G. D.; Protasiewicz, J. D.; Brown, C. E.; Ingold, K. U.; Lusztyk, J. J. Am. Chem. Soc. 1994, 116, 1718. (e) Yamamoto, Y.; Ohno. M.; Eguchi, S. J. Org. Chem. 1996, 61, 9264. To azomethine: Ryu, I.; Matsu, K.; Minakata, S.; Komatsu, M. J. Am. Chem. Soc. 1998, 120, 5838. For an excellent review of acyl radical chemistry, see: Chatgilialoglu. C.; Crich, D.; Komatsu, M.; Ryu, I. Chem. Rev. 1999, 99, 1991.
11. Acyl radical addition to carbonyl: Rust. F. F.; Seubold, F. H.; Vaughan, W. E. J. Am. Chem. Soc. 1948, 70, 3258. (a) Kaplan, L. J. Am. Chem. Soc. 1966, 88, 1833. (b) Urry, W. H.; Nishihara, A.; Niu, J. H. Y. J. Org. Chem. 1967, 32, 347. (c) Harrison, D. A.; Schwartz, R. N.; Kagan, J. J. Am. Chem. Soc. 1970, 92, 5793. (d) Mendenhall, G. D.; Protasiewicz, J. D.; Brown, C. E.; Ingold, K. U.; Lusztyk, J. J. Am. Chem. Soc. 1994, 116, 1718. (e) Yamamoto, Y.; Ohno. M.; Eguchi, S. J. Org. Chem. 1996, 61, 9264. To azomethine: Ryu, I.; Matsu, K.; Minakata, S.; Komatsu, M. J. Am. Chem. Soc. 1998, 120, 5838. For an excellent review of acyl radical chemistry, see: Chatgilialoglu. C.; Crich, D.; Komatsu, M.; Ryu, I. Chem. Rev. 1999, 99, 1991.
12. Acyl radical addition to carbonyl: Rust. F. F.; Seubold, F. H.; Vaughan, W. E. J. Am. Chem. Soc. 1948, 70, 3258. (a) Kaplan, L. J. Am. Chem. Soc. 1966, 88, 1833. (b) Urry, W. H.; Nishihara, A.; Niu, J. H. Y. J. Org. Chem. 1967, 32, 347. (c) Harrison, D. A.; Schwartz, R. N.; Kagan, J. J. Am. Chem. Soc. 1970, 92, 5793. (d) Mendenhall, G. D.; Protasiewicz, J. D.; Brown, C. E.; Ingold, K. U.; Lusztyk, J. J. Am. Chem. Soc. 1994, 116, 1718. (e) Yamamoto, Y.; Ohno. M.; Eguchi, S. J. Org. Chem. 1996, 61, 9264. To azomethine: Ryu, I.; Matsu, K.; Minakata, S.; Komatsu, M. J. Am. Chem. Soc. 1998, 120, 5838. For an excellent review of acyl radical chemistry, see: Chatgilialoglu. C.; Crich, D.; Komatsu, M.; Ryu, I. Chem. Rev. 1999, 99, 1991.
13. Acyl radical addition to carbonyl: Rust. F. F.; Seubold, F. H.; Vaughan, W. E. J. Am. Chem. Soc. 1948, 70, 3258. (a) Kaplan, L. J. Am. Chem. Soc. 1966, 88, 1833. (b) Urry, W. H.; Nishihara, A.; Niu, J. H. Y. J. Org. Chem. 1967, 32, 347. (c) Harrison, D. A.; Schwartz, R. N.; Kagan, J. J. Am. Chem. Soc. 1970, 92, 5793. (d) Mendenhall, G. D.; Protasiewicz, J. D.; Brown, C. E.; Ingold, K. U.; Lusztyk, J. J. Am. Chem. Soc. 1994, 116, 1718. (e) Yamamoto, Y.; Ohno. M.; Eguchi, S. J. Org. Chem. 1996, 61, 9264. To azomethine: Ryu, I.; Matsu, K.; Minakata, S.; Komatsu, M. J. Am. Chem. Soc. 1998, 120, 5838. For an excellent review of acyl radical chemistry, see: Chatgilialoglu. C.; Crich, D.; Komatsu, M.; Ryu, I. Chem. Rev. 1999, 99, 1991.
14. Acyl radical addition to carbonyl: Rust. F. F.; Seubold, F. H.; Vaughan, W. E. J. Am. Chem. Soc. 1948, 70, 3258. (a) Kaplan, L. J. Am. Chem. Soc. 1966, 88, 1833. (b) Urry, W. H.; Nishihara, A.; Niu, J. H. Y. J. Org. Chem. 1967, 32, 347. (c) Harrison, D. A.; Schwartz, R. N.; Kagan, J. J. Am. Chem. Soc. 1970, 92, 5793. (d) Mendenhall, G. D.; Protasiewicz, J. D.; Brown, C. E.; Ingold, K. U.; Lusztyk, J. J. Am. Chem. Soc. 1994, 116, 1718. (e) Yamamoto, Y.; Ohno. M.; Eguchi, S. J. Org. Chem. 1996, 61, 9264. To azomethine: Ryu, I.; Matsu, K.; Minakata, S.; Komatsu, M. J. Am. Chem. Soc. 1998, 120, 5838. For an excellent review of acyl radical chemistry, see: Chatgilialoglu. C.; Crich, D.; Komatsu, M.; Ryu, I. Chem. Rev. 1999, 99, 1991.
15. Acyl radical addition to carbonyl: Rust. F. F.; Seubold, F. H.; Vaughan, W. E. J. Am. Chem. Soc. 1948, 70, 3258. (a) Kaplan, L. J. Am. Chem. Soc. 1966, 88, 1833. (b) Urry, W. H.; Nishihara, A.; Niu, J. H. Y. J. Org. Chem. 1967, 32, 347. (c) Harrison, D. A.; Schwartz, R. N.; Kagan, J. J. Am. Chem. Soc. 1970, 92, 5793. (d) Mendenhall, G. D.; Protasiewicz, J. D.; Brown, C. E.; Ingold, K. U.; Lusztyk, J. J. Am. Chem. Soc. 1994, 116, 1718. (e) Yamamoto, Y.; Ohno. M.; Eguchi, S. J. Org. Chem. 1996, 61, 9264. To azomethine: Ryu, I.; Matsu, K.; Minakata, S.; Komatsu, M. J. Am. Chem. Soc. 1998, 120, 5838. For an excellent review of acyl radical chemistry, see: Chatgilialoglu. C.; Crich, D.; Komatsu, M.; Ryu, I. Chem. Rev. 1999, 99, 1991.
16. Acyl radical addition to carbonyl: Rust. F. F.; Seubold, F. H.; Vaughan, W. E. J. Am. Chem. Soc. 1948, 70, 3258. (a) Kaplan, L. J. Am. Chem. Soc. 1966, 88, 1833. (b) Urry, W. H.; Nishihara, A.; Niu, J. H. Y. J. Org. Chem. 1967, 32, 347. (c) Harrison, D. A.; Schwartz, R. N.; Kagan, J. J. Am. Chem. Soc. 1970, 92, 5793. (d) Mendenhall, G. D.; Protasiewicz, J. D.; Brown, C. E.; Ingold, K. U.; Lusztyk, J. J. Am. Chem. Soc. 1994, 116, 1718. (e) Yamamoto, Y.; Ohno. M.; Eguchi, S. J. Org. Chem. 1996, 61, 9264. To azomethine: Ryu, I.; Matsu, K.; Minakata, S.; Komatsu, M. J. Am. Chem. Soc. 1998, 120, 5838. For an excellent review of acyl radical chemistry, see: Chatgilialoglu. C.; Crich, D.; Komatsu, M.; Ryu, I. Chem. Rev. 1999, 99, 1991.
17. Acyl radical addition to carbonyl: Rust. F. F.; Seubold, F. H.; Vaughan, W. E. J. Am. Chem. Soc. 1948, 70, 3258. (a) Kaplan, L. J. Am. Chem. Soc. 1966, 88, 1833. (b) Urry, W. H.; Nishihara, A.; Niu, J. H. Y. J. Org. Chem. 1967, 32, 347. (c) Harrison, D. A.; Schwartz, R. N.; Kagan, J. J. Am. Chem. Soc. 1970, 92, 5793. (d) Mendenhall, G. D.; Protasiewicz, J. D.; Brown, C. E.; Ingold, K. U.; Lusztyk, J. J. Am. Chem. Soc. 1994, 116, 1718. (e) Yamamoto, Y.; Ohno. M.; Eguchi, S. J. Org. Chem. 1996, 61, 9264. To azomethine: Ryu, I.; Matsu, K.; Minakata, S.; Komatsu, M. J. Am. Chem. Soc. 1998, 120, 5838. For an excellent review of acyl radical chemistry, see: Chatgilialoglu. C.; Crich, D.; Komatsu, M.; Ryu, I. Chem. Rev. 1999, 99, 1991.
18. (a) Takano, S.; Suzuki, M.; Kijima, A.; Ogasawara, K. Chem. Lett. 1990, 315.
19. (b) Takano, S.; Suzuki, M.; Ogasawara, K. Heterocycles 1994, 37, 149.
20. (a) Tomaszewski, M. J.; Warkentin, J. Tetrahedron Lett. 1992, 2123.
21. (b) Tomaszewski, M. J.; Warkentin, J.; Werstiuk, N. H. Aust. J. Chem. 1995, 48, 291.
22. Orito, K.; Uchiito, S.; Satoh, Y.; Tatsuzawa, T.; Harada, R.; Tokuda, M. Org. Lett. 2000, 2, 307.
23. McClure, C. K.; Kiessling, A. J.; Link, J. S. Tetrahedron 1998, 54, 7121.
24. Han, O.; Frey, P. A. J. Am. Chem. Soc. 1990, 112, 8982.
25. Bowman, W. R.; Stephenson, P. T.; Terrett, N. K.; Young, A. R. Tetrahedron Lett. 1994, 35, 6369.
26. Tanner's report of an apparent 5-endo carbon radical cyclization to azomethine nitrogen predates these studies: Tanner, D. D.; Rahimi, P. M. J. Org. Chem. 1979, 44, 1674.
27. Leading references: (a) Copper-promoted: Lindley, J. Tetrahedron 1984, 40, 1433. Lam, P. Y. S.; Duedon, S.; Averill, K. M.; Li, R.; He, M. Y.; DeShong, P.; Clark, C. G. J. Am. Chem. Soc. 2000, 122, 7600. Kwong, F. Y.; Klapars, A.; Buchwald, S. L. Org. Lett. 2002, 4, 581.
28. Leading references: (a) Copper-promoted: Lindley, J. Tetrahedron 1984, 40, 1433. Lam, P. Y. S.; Duedon, S.; Averill, K. M.; Li, R.; He, M. Y.; DeShong, P.; Clark, C. G. J. Am. Chem. Soc. 2000, 122, 7600. Kwong, F. Y.; Klapars, A.; Buchwald, S. L. Org. Lett. 2002, 4, 581.
29. Leading references: (a) Copper-promoted: Lindley, J. Tetrahedron 1984, 40, 1433. Lam, P. Y. S.; Duedon, S.; Averill, K. M.; Li, R.; He, M. Y.; DeShong, P.; Clark, C. G. J. Am. Chem. Soc. 2000, 122, 7600. Kwong, F. Y.; Klapars, A.; Buchwald, S. L. Org. Lett. 2002, 4, 581.
30. (b) Nucleophilic aromatic substitution: Bunnett, J. F. Acc. Chem. Res. 1978, 11, 413. Hattori, T.; Sakamoto, J.; Hayashizaka, N.; Miyano, S. Synthesis 1994, 199.
31. (b) Nucleophilic aromatic substitution: Bunnett, J. F. Acc. Chem. Res. 1978, 11, 413. Hattori, T.; Sakamoto, J.; Hayashizaka, N.; Miyano, S. Synthesis 1994, 199.
32. (c) Electrophilic nitroarenes: Sapountzis, I.; Knochel, P. J. Am. Chem. Soc. 2002, 124, 9390.
33. Palladium-mediated amination, leading references: (a) Wolfe, J. P.; Wagaw, S.; Marcoux, J.-F.; Buchwald, S. L. Acc. Chem. Res. 1998, 31, 805.
34. (b) Hartwig, J. F. Pure Appl. Chem. 1999, 71, 1417.
35. (c) Yang, B. H.; Buchwald, S. L. J. Organomet. Chem. 1999, 576, 125.
36. Johnston, J. N.; Plotkin, M. A.; Viswanathan, R.; Prabhakaran, E. N. Org. Lett. 2001, 3, 1009.
37. Takano reported a 12% yield for this cyclization (ref 6).
38. (a) Beesley, R. M.; Ingold, C. K.; Thorpe, J. F. J. Chem. Soc. 1915, 107, 1080.
39. (b) Ingold, C. K. J. Chem. Soc. 1921, 119, 305.
40. (c) Chatgilialoglu, C.; Ingold, K. U.; Tse-Sheepy, I.; Warkentin. J. Can. J. Chem. 1983, 61, 1077.
41. (d) Beckwith. A. L. J.; Schiesser, C. H. Tetrahedron 1985, 41, 3925.
42. Review: Tedder, J. M. Tetrahedron 1982, 38, 313. For a selected recent example, see: Della, E. W.; Kostakis. C.; Smith, P. A. Org. Lett. 1999, 1, 363.
43. Review: Tedder, J. M. Tetrahedron 1982, 38, 313. For a selected recent example, see: Della, E. W.; Kostakis. C.; Smith, P. A. Org. Lett. 1999, 1, 363.
44. Suehiro, T.; Suzuki, A.; Tsuchida, Y.; Yamazaki, J. Bull. Chem. Soc. Jpn. 1977, 50, 3324.
45. The Alkaloids: Chemistry and Biology; Cordell, G. A., Ed.; Academic: San Diego, 1998; Vol. 50.
46. Asymmetric Heck cyclizations are generally limited to cyclic or 1,1-disubstituted olefins, although exceptions exist: (a) Sato, Y.; Sodeoka, M.; Shibasaki, M. J. Org. Chem. 1989, 54, 4738.
47. (b) Carpenter, N. E.; Kucera, D. J.; Overman, L. E. J. Org. Chem. 1989, 54, 5846.
48. (c) Review: Donde, Y.; Overman, L. E. In Catalytic Asymmetric Synthesis, 2nd Ed.: Ojima, I., Ed.; Wiley: New York, 2000; Chapter 8G.
49. Representative examples: (a) Overman, L. E.; Paone, D. V.; Steams, B. A. J. Am. Chem. Soc. 1999, 121, 7702.
50. (b) Matsuura, T.; Overman, L. E.; Poon, D. J. J. Am. Chem. Soc. 1998, 120, 6500.
51. (c) Nukui, S.; Sodeoka, M.; Sasai, H.; Shibasaki, M. J. Org. Chem. 1995, 60, 398.
52. (d) Takemoto, T.; Sodeoka, M.; Sasai, H.; Shibasaki, M. J. Am. Chem. Soc. 1993, 115, 8477.
53. (e) Ashimori, A.; Matsuura, T.; Overman, L. E.; Poon, D. J. J. Org. Chem. 1993, 58, 6949.
54. Two syntheses of 13 congeners were reported recently, both involving asymmetric hydrogenation (functionalization): (a) Wagaw, S.; Rennels, R. A.; Buchwald, S. L. J. Am. Chem. Soc. 1997, 119, 8451.(b) Kuwano, R.; Sato, K.; Kurokawa, T.; Karube, D.; Ito, Y. J. Am. Chem. Soc. 2000, 122, 7614. For recent interest in Captopril-inspired ACE inhibitors, see: (c) wa Mutahi, M.; Nittoli, T.; Guo, L.; Sieburth, S. McN, J. Am. Chem. Soc. 2002, 124, 7363.
55. Two syntheses of 13 congeners were reported recently, both involving asymmetric hydrogenation (functionalization): (a) Wagaw, S.; Rennels, R. A.; Buchwald, S. L. J. Am. Chem. Soc. 1997, 119, 8451.(b) Kuwano, R.; Sato, K.; Kurokawa, T.; Karube, D.; Ito, Y. J. Am. Chem. Soc. 2000, 122, 7614. For recent interest in Captopril-inspired ACE inhibitors, see: (c) wa Mutahi, M.; Nittoli, T.; Guo, L.; Sieburth, S. McN, J. Am. Chem. Soc. 2002, 124, 7363.
56. Two syntheses of 13 congeners were reported recently, both involving asymmetric hydrogenation (functionalization): (a) Wagaw, S.; Rennels, R. A.; Buchwald, S. L. J. Am. Chem. Soc. 1997, 119, 8451.(b) Kuwano, R.; Sato, K.; Kurokawa, T.; Karube, D.; Ito, Y. J. Am. Chem. Soc. 2000, 122, 7614. For recent interest in Captopril-inspired ACE inhibitors, see: (c) wa Mutahi, M.; Nittoli, T.; Guo, L.; Sieburth, S. McN, J. Am. Chem. Soc. 2002, 124, 7363.
57. Gruenfeld, N.; Stanton, J. L.; Yuan, A. M.; Ebetino, F. H.; Browne, J. J.; Gude, C.; Huebner, C. F. J. Med. Chem. 1983, 26, 1277.
58. There are no asymmetric syntheses of cyclo-Dopa: however, its synthesis from 3,4-dihydroxy phenylalanine has been reported: (a) Buchi, G.; Fliri, H.; Shapiro, R. J. Org. Chem. 1978, 43, 4765.
59. (b) Hermann, K.; Dreiding, A. S. Helv. Chim. Acta 1975, 58, 1805.
60. CBS-type catalysts and their derivatives: (a) Martens, J.; Danelsberg, C.; Behnen, W.; Wallbaum, S. Tetrahedron: Asymmetry 1992, 3, 347. (b) Jones, G. B.; Heaton, S. B.; Chapman, B. J.; Guzel, M. Tetrahedron: Asymmetry 1997, 8, 3625. (S)-Indoline α-amino acid has been used further in asymmetric synthesis after transformation to the derived amino alcohol: (c) hydrogenation - Pasquier, C.; Naili, S.; Mortreux, A.; Agbossou, F.; Pelinski, L.; Brocard, J.; Eilers, J.; Reiners, I.; Peper, V.; Martens, J. Organomet. Chem. 2000, 19, 5723. (d) Asymmetric additions to aldehydes: Asami, M.; Watanabe, H.; Honda, K.; Inoue, S. Tetrahedron: Asymmetry 1998, 9, 4165.
61. CBS-type catalysts and their derivatives: (a) Martens, J.; Danelsberg, C.; Behnen, W.; Wallbaum, S. Tetrahedron: Asymmetry 1992, 3, 347. (b) Jones, G. B.; Heaton, S. B.; Chapman, B. J.; Guzel, M. Tetrahedron: Asymmetry 1997, 8, 3625. (S)-Indoline α-amino acid has been used further in asymmetric synthesis after transformation to the derived amino alcohol: (c) hydrogenation - Pasquier, C.; Naili, S.; Mortreux, A.; Agbossou, F.; Pelinski, L.; Brocard, J.; Eilers, J.; Reiners, I.; Peper, V.; Martens, J. Organomet. Chem. 2000, 19, 5723. (d) Asymmetric additions to aldehydes: Asami, M.; Watanabe, H.; Honda, K.; Inoue, S. Tetrahedron: Asymmetry 1998, 9, 4165.
62. CBS-type catalysts and their derivatives: (a) Martens, J.; Danelsberg, C.; Behnen, W.; Wallbaum, S. Tetrahedron: Asymmetry 1992, 3, 347. (b) Jones, G. B.; Heaton, S. B.; Chapman, B. J.; Guzel, M. Tetrahedron: Asymmetry 1997, 8, 3625. (S)-Indoline α-amino acid has been used further in asymmetric synthesis after transformation to the derived amino alcohol: (c) hydrogenation - Pasquier, C.; Naili, S.; Mortreux, A.; Agbossou, F.; Pelinski, L.; Brocard, J.; Eilers, J.; Reiners, I.; Peper, V.; Martens, J. Organomet. Chem. 2000, 19, 5723. (d) Asymmetric additions to aldehydes: Asami, M.; Watanabe, H.; Honda, K.; Inoue, S. Tetrahedron: Asymmetry 1998, 9, 4165.
63. CBS-type catalysts and their derivatives: (a) Martens, J.; Danelsberg, C.; Behnen, W.; Wallbaum, S. Tetrahedron: Asymmetry 1992, 3, 347. (b) Jones, G. B.; Heaton, S. B.; Chapman, B. J.; Guzel, M. Tetrahedron: Asymmetry 1997, 8, 3625. (S)-Indoline α-amino acid has been used further in asymmetric synthesis after transformation to the derived amino alcohol: (c) hydrogenation - Pasquier, C.; Naili, S.; Mortreux, A.; Agbossou, F.; Pelinski, L.; Brocard, J.; Eilers, J.; Reiners, I.; Peper, V.; Martens, J. Organomet. Chem. 2000, 19, 5723. (d) Asymmetric additions to aldehydes: Asami, M.; Watanabe, H.; Honda, K.; Inoue, S. Tetrahedron: Asymmetry 1998, 9, 4165.
64. Given the unavailability of ent-13, its octahydroindoline derivative is necessarily used to generate the enantiomeric products: Kim, Y. H. Acc. Chem. Res. 2001, 34, 955.
65. Acquisition of ent-10 and related derivatives has relied solely on resolution techniques.
66. O'Donnell, M. J. In Catalytic Asymmetric Synthesis, 2nd Ed.; Ojima, I., Ed.; Wiley-VCH: New York. 2000: Chapter 10.
67. Corey, E. J.; Xu, F.; Noe, M. C. J. Am. Chem. Soc. 1997, 119, 12414.
68. Lygo, B.; Wainwright, P. G. Tetrahedron Lett. 1997, 38, 8595.
69. Crich, D.; Mo, X.-S. J. Am. Chem. Soc. 1998, 120, 8298.
70. (a) Alberti, A.; Bedofni, N.; Benaglia, M.; Leardini, R.; Nanni, D.; Pedulli, G. F.; Tundo, A.; Zanardi, G. J. Org. Chem. 1992, 57, 607.
71. (b) Leardini, R.; Lucarini, M.; Nanni, D.; Pedulli, G. F.; Tundo, A.; Zanardi, G. J. Org. Chem. 1993, 58, 2419.
72. (c) Benati, L.; Placucci, G.; Spagnolo, P.; Tundo, A.; Zanardi, G. J. Chem. Soc., Perkin Trans. 1 1977, 1684.
73. Kin, S.; Joe, S. H.; Do, J. Y. J. Am. Chem. Soc. 1994, 116, 5521.
74. 3SnH under thermal or free radical conditions is a well-established reaction: (a) Newmann, W. P.; Heymann, E. Liebigs Ann. Chem. 1965, 683, 249. (b) Werry, J.; Stamm, H.; Lin, P.-Y.; Falkenstein, R.; Gries, S.; Irngartinger, H. Tetrahedron 1989, 45, 5015.
75. 3SnH under thermal or free radical conditions is a well-established reaction: (a) Newmann, W. P.; Heymann, E. Liebigs Ann. Chem. 1965, 683, 249. (b) Werry, J.; Stamm, H.; Lin, P.-Y.; Falkenstein, R.; Gries, S.; Irngartinger, H. Tetrahedron 1989, 45, 5015.
76. Alberti, A.; Hudson, A.; Pedulli, G. J. Chem. Soc., Faraday Trans. 2 1980, 76, 948.
77. Cox, A. L.; Johnston, J. N. Org. Lett. 2001, 3, 3695.